With combustion machines, especially such as are operated with two different fuels, oil as a fuel is typically injected via swirl ducts in which the oil is mixed with air. For improved mixing of oil and air a swirling movement is imparted to the oil within the nozzles used for injection. This swirl generation has previously been achieved by these nozzles consisting of number of small plates having small holes at coordinates which deviate slightly from one another. By soldering together the individual plates a spiral is produced which is used for swirling the fuel. However such nozzles have a complicated layout in construction terms since the holes must be placed exactly.